Integrated analysis of climatic controls on vegetation productivity and resulting carbon sink stability across eco-geographical regions of China

Understanding the spatially divergent responses of terrestrial vegetation to climatic drivers is essential for predicting carbon dynamics and guiding regional climate adaptation. Utilizing MODIS Gross Primary Productivity (GPP) and high-resolution meteorological datasets (2000–2020), this study investigates the spatiotemporal evolution, climatic sensitivities, and carbon sink stability across China’s nine eco-geographical regions. Over the past two decades, China’s terrestrial GPP exhibited a fluctuating upward trajectory (averaging 350.4 gC·m⁻²·a⁻¹), characterized by a persistent “high in the east, low in the west” spatial gradient. The climate-vegetation interactions demonstrated profound regional heterogeneity. For instance, vegetation in the North Subtropical Zone showed extreme sensitivity to moisture (r = 0.993 with precipitation), whereas the Marginal Tropical Zone was predominantly regulated by thermal conditions (r = 0.811 with temperature). Notably, the high-altitude Plateau Temperate Zone exhibited significant negative correlations with both drivers, highlighting its severe vulnerability to combined climatic stressors. Furthermore, by introducing a persistence-based stability framework, we found that the Cold-Temperate and South Subtropical Zones act as exceptionally stable carbon sinks (> 97% persistent sink area). Conversely, western regions (e.g., Tibetan Plateau hinterland) operate as persistent carbon sources, with localized source-sink transitions indicating high ecological fragility. These findings underscore that national carbon neutrality goals require highly differentiated, biome-specific ecological management strategies rather than uniform policies.